Wrapped up an example in README.md

README.md

@@ -35,26 +35,28 @@ extern crate rand;
 
 use rand::prelude::*;
 
-// basic usage with random():
-let x: u8 = random();
-println!("{}", x);
+fn main() {
+  // basic usage with random():
+  let x: u8 = random();
+  println!("{}", x);
 
-let y = random::<f64>();
-println!("{}", y);
+  let y = random::<f64>();
+  println!("{}", y);
 
-if random() { // generates a boolean
-    println!("Heads!");
-}
+  if random() { // generates a boolean
+      println!("Heads!");
+  }
 
-// normal usage needs both an RNG and a function to generate the appropriate
-// type, range, distribution, etc.
-let mut rng = thread_rng();
-if rng.gen() { // random bool
-    let x: f64 = rng.gen(); // random number in range (0, 1)
-    println!("x is: {}", x);
-    let ch = rng.gen::<char>(); // Sometimes you need type annotation
-    println!("char is: {}", ch);
-    println!("Number from 0 to 9: {}", rng.gen_range(0, 10));
+  // normal usage needs both an RNG and a function to generate the appropriate
+  // type, range, distribution, etc.
+  let mut rng = thread_rng();
+  if rng.gen() { // random bool
+      let x: f64 = rng.gen(); // random number in range (0, 1)
+      println!("x is: {}", x);
+      let ch = rng.gen::<char>(); // Sometimes you need type annotation
+      println!("char is: {}", ch);
+      println!("Number from 0 to 9: {}", rng.gen_range(0, 10));
+  }
 }
 ```